Breaking device for a chain of a screen, such as a window covering

摘要

The invention relates to a breaking device for a chain (5) of a screen, comprising a housing formed by a first and a second housing part (10, 20), that are attachable to each other by a detachable coupling. In operational position a first and a second toothed wheel (11, 21) are in engagement with each other and the chain engages onto a sprocket (12) connected to the first toothed wheel (11). The detachable coupling is arranged to release when a pulling force on the chain, reaches or exceeds a predetermined threshold value. The first toothed wheel (11) and the second toothed wheel (21) are mutually positioned such that the chain (5) has an engagement side (5A) and a non-engagement side (5B), such that the pulling force (F up ) on the engagement side (5A) can be larger than the pulling force (F down ) on the non-engagement side (5B).